The present invention relates generally to foundry equipment and, more particularly, an improved treating ladle for use in the production of ductile iron by the treating of molten base iron with a treatment alloy.
The production of ductile iron generally involves the treatment of a low sulfur base iron with a magnesium alloy within a treating ladle, usually resulting in a production of a certain amount of slag. The bottom of a treating ladle includes a pocket in which the magnesium alloy is deposited before being covered with molten iron for treatment therewith. This pocket is subject to wear of the refractory lining and to a slag build-up which occasionally needs to be removed to maintain the integrity of the pocket.
In the past, the use of an open treating ladle resulted in the generation of a flare and exhaust fumes to the extent that the installation of exhaust hoods have been necessary to meet environmental standards. The development of a tundish cover by R. D. Forrest and H. Wolfensberger for placement over the top of an open treating ladle resulted in significant reductions of both flare and exhaust fumes. However, the Forrest and Wolfensberger tundish cover design requires a manual placement of the cover on the ladle before treatment of the iron and a removal of the cover after treatment to provide for the removal of slag and dross, as well as the addition of magnesium alloy for the subsequent treatment. Accordingly, the weight of the tundish cover was necessarily limited, preventing the use of sufficient refractory in the tundish cover and resulting in frequent failures of the tundish box.
Additional difficulties were encountered with the maintenance and repair of the bottom of the treating ladle, particularly in and around the pocket formed therein. Because of the depth of the treating ladle required to hold approximately 1400 pounds of molten base iron, it is difficult to reach the bottom of the pocket to remove any slag build-up therefrom. In addition, the greatest amount of lining erosion occurs around the pocket curve, resulting in the need to patch this region on a regular basis.